2D animation, Line between meshes
Im not sure if i understood you correctly, but I try it anyways.
I used a Path with a Circle as a Bevel Object. Watch in the Path settings. The Bevel Circle is on Layer 2.

The workflow for Hook 2 Objects:


Select your Mesh
Shift+Select your Path
Press TAB to switch to Edit Mode
Select the Point of the Path you want to Hook to
Ctrl+H > Hook to selected Object
Done




Here is an example File. I hope I could help.